[PATCH 1/8] mm: use vm_unmapped_area() on parisc architecture

From: Michel Lespinasse
Date: Wed Jan 23 2013 - 20:30:07 EST


Update the parisc arch_get_unmapped_area function to make use of
vm_unmapped_area() instead of implementing a brute force search.

Signed-off-by: Michel Lespinasse <walken@xxxxxxxxxx>
Acked-by: Rik van Riel <riel@xxxxxxxxxx>

---
arch/parisc/kernel/sys_parisc.c | 46 ++++++++++++++------------------------
1 files changed, 17 insertions(+), 29 deletions(-)

diff --git a/arch/parisc/kernel/sys_parisc.c b/arch/parisc/kernel/sys_parisc.c
index f76c10863c62..6ab138088076 100644
--- a/arch/parisc/kernel/sys_parisc.c
+++ b/arch/parisc/kernel/sys_parisc.c
@@ -35,18 +35,15 @@

static unsigned long get_unshared_area(unsigned long addr, unsigned long len)
{
- struct vm_area_struct *vma;
+ struct vm_unmapped_area_info info;

- addr = PAGE_ALIGN(addr);
-
- for (vma = find_vma(current->mm, addr); ; vma = vma->vm_next) {
- /* At this point: (!vma || addr < vma->vm_end). */
- if (TASK_SIZE - len < addr)
- return -ENOMEM;
- if (!vma || addr + len <= vma->vm_start)
- return addr;
- addr = vma->vm_end;
- }
+ info.flags = 0;
+ info.length = len;
+ info.low_limit = PAGE_ALIGN(addr);
+ info.high_limit = TASK_SIZE;
+ info.align_mask = 0;
+ info.align_offset = 0;
+ return vm_unmapped_area(&info);
}

#define DCACHE_ALIGN(addr) (((addr) + (SHMLBA - 1)) &~ (SHMLBA - 1))
@@ -63,30 +60,21 @@ static unsigned long get_unshared_area(unsigned long addr, unsigned long len)
*/
static int get_offset(struct address_space *mapping)
{
- int offset = (unsigned long) mapping << (PAGE_SHIFT - 8);
- return offset & 0x3FF000;
+ return (unsigned long) mapping >> 8;
}

static unsigned long get_shared_area(struct address_space *mapping,
unsigned long addr, unsigned long len, unsigned long pgoff)
{
- struct vm_area_struct *vma;
- int offset = mapping ? get_offset(mapping) : 0;
-
- offset = (offset + (pgoff << PAGE_SHIFT)) & 0x3FF000;
+ struct vm_unmapped_area_info info;

- addr = DCACHE_ALIGN(addr - offset) + offset;
-
- for (vma = find_vma(current->mm, addr); ; vma = vma->vm_next) {
- /* At this point: (!vma || addr < vma->vm_end). */
- if (TASK_SIZE - len < addr)
- return -ENOMEM;
- if (!vma || addr + len <= vma->vm_start)
- return addr;
- addr = DCACHE_ALIGN(vma->vm_end - offset) + offset;
- if (addr < vma->vm_end) /* handle wraparound */
- return -ENOMEM;
- }
+ info.flags = 0;
+ info.length = len;
+ info.low_limit = PAGE_ALIGN(addr);
+ info.high_limit = TASK_SIZE;
+ info.align_mask = PAGE_MASK & (SHMLBA - 1);
+ info.align_offset = (get_offset(mapping) + pgoff) << PAGE_SHIFT;
+ return vm_unmapped_area(&info);
}

unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
--
1.7.7.3
--
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